Fluid filled unit formation machine and process

ABSTRACT

A machine for the manufacture of inflated plastic dunnage and other fluid filled units is disclosed. In a disclosed and pictured dunnage embodiment, the machine includes a hollow shaft rotatably mounted on a frame. In the preferred embodiment the shaft is solid. With either embodiment a drive is operably connected to the shaft for causing the shaft to rotate about its axis and a drum mounted on the shaft to rotate with the shaft. The drum is in the form of a pair of closely spaced discs having perimetral, cylindrically contoured sealing surfaces for support and, in cooperation with driven metal belts, transport of a web being formed into dunnage units. Sets of heating and cooling shoes having spaced arcuate surfaces are complementally positioned adjacent the drum surfaces with the cooling shoes downstream from the heating shoes in the direction of dunnage formation rotation. A nozzle is mounted generally tangentially of the drum at a location midway between the discs. Each of the cooling shoes includes an air expansion chamber communicating through a shoe inlet when in use with a supply of air under pressure. In the hollow shaft embodiment one cooling shoe chamber has an outlet in communication with the nozzle via the shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Divisional of U.S. patent application Ser. No. 10/408,947filed Apr. 8, 2003 for FLUID FILLED UNIT FORMATION MACHINE AND PROCESS,now U.S. Pat. No. 6,889,739.

FIELD OF INVENTION

This invention relates to a novel machine and process for producingdunnage and other fluid filled units with a novel web.

BACKGROUND OF THE INVENTION

U.S. Pats. Re 36,501 reissued Jan. 18, 2000 and RE 36,759 reissued Jul.4, 2000 respectively entitled “Method for Producing Inflated Dunnage”and “Inflated Dunnage and Method for its Production” and based onoriginal patents respectively issued Sep. 3, 1996 and Dec. 2, 1997 toGregory A. Hoover et al. (the Hoover Patents) disclose a method forproducing dunnage utilizing preopened bags on a roll. The preopened bagsutilized in the Hoover patents are of a type disclose in U.S. Pat. No.3,254,828 issued Jun. 2, 1966 to Hershey Lerner and entitled “FlexibleContainer Strips” (the Autobag Patent). The preferred bags of the Hooverpatents are unique in that the so called tack of outer bag surfaces isgreater than the tack of the inner surfaces to facilitate bag openingwhile producing dunnage units which stick to one another when in use.

U.S. Pat. No. 6,199,349 issued Mar. 13, 2001 under the title DunnageMaterial and Process (the Lerner Patent) discloses a chain ofinterconnected plastic pouches which are fed along a path of travel to afill and seal station. As each pouch is positioned at the fill stationthe pouches are sequentially opened by directing a flow of air through apouch fill opening to open and then fill the pouch. Each filled pouch isthen sealed to create an hermetically closed, inflated dunnage unit.Improvements on the pouches of the Lerner Patent are disclose incopending applications Ser. No. 09/735,345 filed Dec. 12, 2000 and Ser.No. 09/979,256 filed Nov. 21, 2001 and respectively is entitled DunnageInflation (the Lerner Applications). The system of the Lerner Patent andApplications is not suitable for packaging liquids. Moreover, since theproduction of dunnage units by the process described is relatively slow,an accumulator is desirable. An improved accumulator and dispenser forreceiving dunnage units manufactured by a dunnage unit formation machineis disclose in U.S. application Ser. No. 09/735,111 filed Dec. 12, 2000by Rick S. Wehrmann under the title Apparatus and Process for DispensingDunnage.

Accordingly, it would be desirable to provide an improved system forfilling pouches with fluid to produce dunnage or liquid filled units athigh rates of speed.

SUMMARY OF THE INVENTION

The machine and process of the present invention provide enhancedproduction of dunnage units similar to those produced by the systems ofthe Lerner Patent and Applications but at greatly improved productionrates. Unlike those systems, the machine and process of the presentinvention are also capable of producing liquid filled units.Specifically, a novel and improved unit formation machine is disclosed.The machine includes a rotatable drum having a spaced pair ofcylindrically contoured surfaces. An elongated nozzle extends generallytangentially between and from the cylindrical surfaces. In use, thenozzle is inserted into a novel web at a transversely centered positionas the web is fed upwardly and around the drum. The web is described andclaimed in a concurrently filed application Ser. No. 10/408,946 byHershey Lerner. As the web passes over the nozzle, web pouches arefilled with fluid and the web is separated into two chains of filledpouches as the nozzle assembly separates the web along longitudinallines of weakness.

A plurality of heat shoes are provided. Each heat shoe has a spaced pairof arcuate web engaging surfaces which are complemental with thecylindrical drum surfaces. Downstream from the heat shoes in thedirection of web travel, a plurality of cooling shoes \are provided. Thecooling shoes like the heating shoes have pairs of arcuate surfaceswhich are complemental with the drum's cylindrical surfaces. The shoesare effective to clamp a pair of metal transport belts against the weband in turn the web against the rotating drum as spaced sets of sealsare formed. The seals complete fluid filled pouches and convert thefilled pouches into dunnage or liquid filled units. The units areseparated following their exit from the last of the cooling shoes.

Tests of dunnage manufacture have shown that with pouches having fourinch square external dimensions, dunnage units are produced at the rateof eight cubic feet per minute. This contrasts sharply with the machineof the Lerner Patents which produces dunnage units at the rate of threecubic feet per minute. Indeed the system of the present inventionproduces dunnage units on demand at rates sufficiently fast to obviatethe need for a device such as that taught in The Dispenser Patent.

One of features of a dunnage only embodiment of the machine of thepresent invention is the novel and efficient way in which it utilizesair under pressure. Pressurized air is fed to chambers within thecooling shoes where it is allowed to expand. As the air expands in thecooling shoe chambers, it absorbs heat, enabling the shoes effectivelyto freeze seals of dunnage units being formed.

The drum in the disclosed embodiments is in fact a slightly spaced pairof disks mounted on a driven and rotatable shaft. In the dunnage onlyembodiment the drum shaft is tubular. Air exhausted from the coolingshoes is fed to the tubular shaft and thence through an axially centeredshaft outlet to a connected nozzle. Air supplied to the nozzle furtherexpands as the pouches are inflated. The result is even though the airexpands as pouches are inflated, the air within the pouches is warmerthan ambient. As the air within the pouches, and thus the dunnage unitsbeing formed reaches equilibrium with the ambient temperature, pressurewithin the units will decrease sufficiently to assure that the finisheddunnage units, while solidly filled, are filled at controlled pressurelow enough to minimize the potential for rupture when compressed in use.

Accordingly the objects of the invention are to provide a novel andimproved dunnage formation machine and process of formation of fluidfilled units.

In the Drawings:

FIG. 1 is an elevational view of the unit formation machine of thepresent invention;

FIG. 2 is a plan view of the machine of FIG. 1 as seen from the planeindicated by the line 2—2 of FIG. 1 showing a web being fed into themachine;

FIG. 3 is an enlarged sectional view of a heat shoe and a portion of thedrum as seen from the plane indicated by the line 3—3 of FIG. 1;

FIG. 3 a is a further enlarged view of the shoe and the drum as seenfrom the same plane as FIG. 3;

FIG. 4 is a view showing a dunnage embodiment of the machine withcomponents which delineate a air flow path from a supply to and throughthe cooling shoes and then the inflation nozzle;

FIG. 5 is a perspective view of a section of the novel and improved web;

FIG. 6 is a perspective view showing a section of a web as the webpouches are inflated and the web is separated into parallel rows ofinflated pouches;

FIG. 7 is an enlarged plan view of a portion of the web including atransverse pair of heat seals;

FIG. 8 is a further enlarged fragmentary view of a central part of theweb as located by the circle in FIG. 7;

FIG. 9 is a perspective view showing a pair of completed fluid filledunits following separation and as they exit the machine; and,

FIG. 10 is an enlarged view of a preferred support embodiment and a shoewhich arrangement is for supporting the shoes in their use positions andfor moving them to out of the way positions for machine set up andservice.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

While the following description describes a dunnage formation system, itshould be recognized the preferred embodiment of the machine issterilzable so that beverages such as water and fruit juice may bepackaged using the novel web, machine and process.

Referring now to the drawings and FIGS. 1 and 2 in particular, a dunnageformation machine is shown generally at 10. The machine includes arotatable drum 12 which is driven by a motor 14 via a gear box 15 and abelt and pulley arrangement 16, FIG. 2. In the preferred and disclosearrangement, the drum is comprised of spaced annular disks 18.

When the machine is in use a web 20 is fed from a supply, not shown. Asis best seen in FIG. 1, the web 20 passes over a guide roll 22 andthence under a guide roll 24 to an inflation station 25. The web 20 isfed around the disks 18 to pass under, in the disclose embodiment, threeheat shoes 26 which shoes heat metal transport belts 27 to seal layersof the web. The heat softened web portions and the transport belts thenpass under cooling shoes 28 which freeze the seals being formed. As thenow inflated and sealed web passes from the cooling shoes individualdunnage units 30 are dispensed.

In practice the machine 10 will be housed within a cabinet which is notshown for clarity of illustration. The cabinet includes access doorswith an electrical interlock. When the doors are open the machine may bejogged for set up, but the machine will not operate to produce dunnageunits unless the doors are closed and latched.

The Web

Referring now to FIGS. 5–9, the novel and improved web for formingdunnage units is disclose. The web is formed of a heat sealable plasticsuch as polyethylene. The web includes superposed top and bottom layersconnected together at spaced side edges 32. Each of the side edges is aselected one of a fold or a seal such that the superposed layers arehermetically connected along the side edges 32.

A plurality of transverse seal pairs 34 are provided. As best seen inFIGS. 5–7, each transverse seal extends from an associated side edge 32toward a longitudinally extending pair of lines of weakness 35. Thelongitudinal lines of weakness 35 are superposed one over the other inthe top and bottom layers of the web and are located midway between theside edges. Each transverse seal 34 terminates in spaced relationshipwith the longitudinal lines of weakness which preferably are in the formof uniform, small perforations. The transverse seal pairs 34 togetherwith the side edges 32 delineate two chains of centrally open sideconnected, inflatable pouches 37.

As is best seen in FIGS. 7 and 8, transverse lines of weakness 36 areprovided. The pouches are separable along the transverse lines 36. Likethe longitudinal lines of weakness 35 the transverse lines arepreferably perforations but in contrast to the to the longitudinal lineperforations each has substantial length. The perforations of thetransverse lines 36, in a further contrast with the perforations of thelongitudinal lines 35, are not of uniform dimension longitudinally ofthe lines. Rather, as is best seen in FIG. 8, a pair of small or shortperforations 38 is provided in each line. The small perforations 38 ofeach pair are disposed on opposite sides of and closely spaced from thelongitudinal lines 34. Each transverse line of weakness also includes apair of intermediate length perforations 40 which are spaced andpositioned on opposite sides of the small perforations 38. Theintermediate perforations extend from unsealed portions of thesuperposed layers into the respective seals of the associated transverseseal pair. The remaining perforations of each line are longer than theintermediate perforations 40.

The Machine

In the embodiment of FIG. 1, the disks 18 are mounted on a tubular shaft42. The shaft 42 is journaled at 44 for rotation driven by the belt andpulley arrangement 16. The shaft 42 carries a stationary, tubular,nozzle support 45 which extends from around the shaft 42 radiallyoutwardly. A nozzle assembly 46 is carried by a support arm 45A, FIG. 6.The nozzle assembly 46 includes an inflation nozzle 48. As is best seenin FIG. 6, the nozzle 48 is an elongated tube with a closed, generallyconical, lead end portion 49. The nozzle 48 when in use extends into theweb at a central location transversely speaking. The web transverselines of weakness are spaced slightly more than a one half thecircumference of the nozzle so that the web layers fit closely aroundthe nozzle to minimize leakage of air exiting side passages 51 of thenozzle to inflate the pouches 37.

The nozzle assembly 46 includes a web retainer 50 which guides the webagainst the nozzle 48. The retainer also functions to cause the web tobe longitudinally split along the longitudinal lines of weakness 35 intotwo strips of inflated pouches.

As is best seen in FIGS. 3 and 3A, each of the heat shoes 26 has amirror image pair of heat conductive bodies 52. The bodies 52 togetherdefine a cylindrical aperture 54, which houses a heating element, notshown. Each heat body 52 includes a seal leg 55 having an arcuatesurface substantially complemental with a cylindrical surface of anassociated one of the disks 18. In the disclose embodiment the disksurfaces are defined by thermally conductive silicone rubber inserts 18s, FIG. 3A. In the embodiment of FIGS. 3 and 3A, springs 56 bias thelegs 55 against the transport belts 27 as the web passes under the heatshoes due to rotation of the drum 12 and its disks 18. The cooling shoes38 are mounted identically to the heat shoes.

Each cooling shoe 28 includes an expansion chamber 58, FIG. 4. An airsupply, not shown, is connected to a chamber inlet 60. Air underpressure is fed through the inlet 60 into the chamber 58 where the airexpands absorbing heat and thus cooling the shoe. Exhaust air from thechamber passes through an exit 62. Cooling shoe legs 63 are biasedagainst the web to freeze the heat softened plastic and complete seals.

In the embodiment of FIGS. 1–4 cooling shoe exhaust air then passesthrough a conduit 64 to the tubular shaft 42. Air from the cooling shoesis fed via the conduit 64 and the shaft 42 to a passage 65 in the nozzlesupport 45. The passage 65 is connected to the nozzle 48. Thus air fromthe cooling shoes is directed to and through the nozzle 48 and the exitpassages 51 into the pouches.

With the now preferred and sterilizable embodiment, cooling shoes 28′ asshown in FIG. 10 are employed has a jacket 67 which surrounds a bodyhaving cooling fins shown in dotted lines in FIG. 10. An inlet 60′ isprovided at the top of the jacket. Air flowing from the inlet passesover the fins cooling them and the exits from the bottom of the jacket.Each of the shoes 28′ is vented to atmosphere through an outlet 67. Thenozzle 48 is directly connected to a supply of fluid under pressure andthe shaft 42 may be made of solid material.

A pair of hold down belts 66 are mounted on a set of pulleys 68. Thebelts 66 are reeved around a major portion of the disks 18. As is bestseen in FIGS. 3 and 3A, the belts 66 function to clamp portions of theweb 20 against the disks on opposite sides of the shoe legs 55. Whiletest have shown that the machine is fully operable without the belts 66,they are optionally provided to isolate pressurized air in the inflatedpouches 37 from the heating and cooling shoes. A fixed separator 69 isprovided. As the inflated pouches approach the exit from the downstreamcooling shoe the fixed separator functions to cam them radiallyoutwardly sequentially to separate each dunnage unit from the nexttrailing unit along the connecting transverse line of weakness exceptfor a small portion under the transport belts 27.

A separator wheel 74 is provided, FIG. 1. The wheel 74 is rotatedclockwise as seen in FIG. 1 such that arms 76 are effective to engagecompleted dunnage units 30 sequentially to complete the separation ofeach dunnage unit from the web along its trailing transverse line ofweakness 36. Thus, the separator wheel is effective to tear the lastsmall connection of each pouch which was under an associated one of thetransport belts as the pouch was substantially separated by the fixedseparator 69.

In the embodiment of FIG. 1, each of the shoes 26, 28 is mounted on anassociated radially disposed shaft 71. Clamping arrangements showngenerally at 72 are provided to fix each of the shafts 71 in an adjustedposition radially of and relative to the drum 12. As is best seen inFIG. 3, each shaft 71 carries a yoke 73. The springs 56 span betweenyoke pins 75 and shoe pins 75 to bias the shoes against a web 20. Acylinder 70 is provided for elevating a connected yoke and shoe formachine set up and service.

In the now preferred embodiment of FIG. 10, each shoe is pivotallymounted on an arm 78. The arm is also pivotally mounted at 80 on a frame82. A cylinder 70′ spans between the arm and the frame for elevating theconnected shoe for set up and service and for urging the shoes 28 intotheir operating positions. The heat shoes 26 are, in the now preferredarrangement, identically mounted.

Operation

In operation, the shoes are elevated by energizing the cylinders 70 ofFIGS. 1 and 4 or 70′ of FIG. 10. A web 20 is fed along a path of travelover the guide roll 22 and under the guide roll 24 and thence threadedover the inflation nozzle 48. The web is then fed under the transportbelts and the retainer 50. As the machine is jogged to feed the webaround the discs 18 and the heating and cooling shoes 26,28 the web issplit by the nozzle support 55. The split of the web is along thelongitudinal line of weakness but the transverse lines of weaknessremain intact at this time. Thus, the web portions at opposite ends ofthe small perforations 38 are of sufficient size and strength to avoid alongitudinal split of the web as the web is fed over the nozzle. Sincethe transverse seals of each pair are spaced only very slightly morethan one half the circumference of the nozzle the web closely surroundsthe nozzle to minimize air leakage when the pouches are inflated.

Next the heating and cooling shoes are elevated by actuating either thecylinders 70 or 70′. The web is then fed sequentially, and one at atime, under the heating shoes 26 and the cooling shoes 28. Since the webhas been split by the nozzle support 55, there are in fact two parallelpaths of travel each with an associated transport belt 27 and chain ofside connected and inflated pouches.

Once the web has been fed around the drum to an exit location near theseparator wheel 74 and the machine has been jogged until the operator issatisfied the feed is complete and the machine is ready, the heat shoeelements will be energized. Air will be supplied to the cooling shoes 28and the nozzle 48. Next the motor 14 will be energized to commencemachine operation.

As we have suggested, one of the outstanding features of the inventionis that the web closely surrounds and slides along the nozzle. The closesurrounding is assured by the transverse seals being spaced a distancesubstantially equal to one half the circumference of the nozzle 48.Thus, the two web layers together delineate a nozzle receiving spacewhich will closely surround an inserted nozzle. As the web advances thepouches 37 on opposed sides of the nozzle will be filled efficiently byfluid under pressure exiting the nozzle passages 51 in opposed streams.Where dunnage units are being formed the fluid will be air. The web isthen split by the nozzle support into two chains of side connected andfluid filled pouches respectively traveling along associated ones of thetwo paths of travel.

Each of the chains is fed under spaced legs 55 of the heating shoes 26to effect heat seals. As the web passes under cooling shoe legs 63 theseals are frozen and the pouches are separated along most of the lengthof transverse lines of weakness by the separator. Facile separation isassured by the long perforations because the remaining connections ofthe web across the transverse seals are short in transverse dimensionand few in number.

When the pouches exit the last of the cooling shoes, they have beenformed into finished dunnage units 30. The finished units 30 aresequentially completely separated from the web by the arms 76 of theseparation wheel 74.

While the system as disclosed and described in the detailed descriptionis directed to dunnage, again, as previously indicated, units filledwith fluids other than air such as water and fruit juices can beproduced with the same machine, process and web.

Although the invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by way of exampleand that numerous changes in the details of construction, operation andthe combination and arrangement of parts may be resorted to withoutdeparting from the spirit and the scope of the invention as hereinafterclaimed.

1. A process of forming fluid filled units comprising: a) feeding a webhaving a series of side connected pouches that are each connected to anadjacent pouch by a line of perforations from a supply to a fillstation, wherein first perforations of the line of perforations thatextend from an inflation opening of each pouch are shorter than secondperforations of the line of perforations that extend from the firstperforations toward a side edge of each pouch; b) fluid filling thepouches as the web is fed through the fill station by directing fluidunder pressure through a nozzle into the web pouches; c) maintaining theweb in close surrounding relationship with the nozzle during the fillingstep to limit the loss of fluid under pressure from the web; and, d)sealing the pouches to form filled units by engaging the web with beltsand passing engaged web portions under coacting heating and coolingshoes.
 2. The process of claim 1 wherein there are spaced pairs of sideconnected pouches and the pouches of each pair are concurrently formedinto dunnage units.
 3. The process of claim 1 wherein there are spacedpairs of side connected pouches and the pouches of each pair areconcurrently formed into units.